1. Field
The present invention relates to a light emitting diode (LED) and a method of fabricating the same, and more particularly, to an LED having a photonic crystal structure and a method of fabricating the same.
2. Discussion of the Background
GaN-based light emitting diodes (LEDs) are widely used for display elements and backlights. Further, these LEDs have less electric power consumption and a longer lifespan as compared with conventional light bulbs or fluorescent lamps, so that their application areas have been expanded for general illumination while substituting for conventional incandescent bulbs and fluorescent lamps. Recently, deep ultraviolet (DUV) LEDs for emitting DUV light with the wavelength of 365 nm or less have been developed. The DUV LEDs can be variously applied to air and water sterilization, removal of surface pollutant, a photo-sensor such as a bio-agent detector, UV curing of polymer, medical analysis equipment, and the like.
In general, a DUV LED has a structure in which a multiple quantum well structure including a GaN-based well layer containing Al is interposed between an n-type AlGaN layer and a p-type AlGaN layer so as to emit short-wavelength light. Meanwhile, since the AlGaN layer does not generally come in ohmic contact with a metal, a p-type contact layer of GaN or quaternary AlInGaN having a small content of Al is employed. However, since the p-type contact layer is not transparent enough for DUV light to pass therethrough, a flip-chip bonding technique is employed so that UV light can be emitted through a transparent substrate.
Since a considerable amount of light emitted in the multiple quantum well structure is absorbed in the p-type contact layer, the light efficiency of the DUV LED is very low.